1. Field of the Invention
This invention relates to a rotation axis fine adjustment apparatus for finely pivoting a rotation axis (or a pivot axis), and more particularly to a rotation axis fine adjustment apparatus in which a fine adjustment control handle and a fastening control handle are provided on a co-axis.
Conventional surveying equipment such as theodolites, levels, light wave range finders, etc. is provided with a rotation axis fine adjustment apparatus in order to permit a mounting portion supporting a telescope portion to be finely rotated around a horizontal axis or a vertical axis.
There is known a rotation axis fine adjustment apparatus of this type as disclosed, for example, in Japanese Utility Model Application No. 56(1981)-116700 filed in the same name of the present applicant, wherein a fastening control handle for tightening a fastening frame to a rotation axis and fasten its rotation, and a fine adjustment control handle for finely rotating a mounting portion fastened are provided on a co-axis. This type of a rotation axis fine adjustment apparatus employs a co-axial construction comprising a fine adjustment axial body having a male thread portion which is rotatable integrally with a fine adjustment control handle, and a fastening cylindrical body portion having a female thread portion for engaging with the male thread portion at its inner periphery which is rotated by operating a fastening control handle provided on a coaxis with the fine adjustment control handle.
However, in a rotation axis fine adjustment apparatus of this type, the female thread portion for engaging the male thread portion is integrally formed with the fastening control handle. After the fastening control handle is operated to permit it to be rotated integrally with the mounting portion, the fine adjustment handle is operated to effect a fine adjustment. At this time, there arises such a problem as that the fastening control handle itself is rotated due to the reaction force of the thread portion.
The present invention was accomplished in order to overcome the problem inherent in the related art.